1. Technical Field
The present invention relates to an optical waveguide, an optical printed circuit board equipped with the optical waveguide, and methods of manufacturing the optical waveguide and the optical printed circuit board.
2. Description of the Related Art
With recent advances in computer and communication technology, the transfer rate of signals in electronic equipment has become an important parameter. However, in the case of a regular printed circuit board, a conductive metal such as copper, etc., may be used for the electrical wiring as the medium for signal transfer, and there may be limits to transmitting high capacities of data at high speeds. As a way to overcome such limits, the optical printed circuit board has been developed, in which an optical waveguide may be embedded in the printed circuit board.
Here, an optical waveguide may be composed of a center portion having a high refractive index, known as the core, and a surrounding portion having a low refractive index, known as the cladding. Within the optical waveguide, light may undergo repeated total reflection at the boundary between the core and cladding, and in this way, an optical waveguide makes it possible to transfer optical signals.
In the case of an optical printed circuit board based on the related art, the core and the cladding may both be made from transparent materials, making it difficult to distinguish the cladding and the core from each, other or to identify the position of the core inserted in the cladding. Thus, when forming circuit patterns, via lands, or solder resist, etc., over the optical waveguide, it may be difficult to align these elements with respect to the core.